Sustainable management of plastic wastes in COVID-19 pandemic: The biochar solution.

To prevent the COVID-19 transmission, personal protective equipment (PPE) and packaging materials have been extensively used but often managed inappropriately, generating huge amount of plastic waste. In this review, we comprehensively discussed the plastic products utilized and the types and amounts of plastic waste generated since the outbreak of COVID-19, and reviewed the potential treatments for these plastic wastes. Upcycling of plastic waste into biochar was addressed from the perspectives of both environmental protection and practical applications, which can be verified as promising materials for environmental protections and energy storages. Moreover, novel upcycling of plastic waste into biochar is beneficial to mitigate the ubiquitous plastic pollution, avoiding harmful impacts on human and ecosystem through direct and indirect micro-/nano-plastic transmission routes, and achieving the sustainable plastic waste management for value-added products, simultaneously. This suggests that the plastic waste could be treated as a valuable resource in an advanced and green manner.

Characterization of bioenergy biochar and its utilization for metal/metalloid immobilization in contaminated soil.

This study is a comparison of the effect of biochar produced by bioenergy systems, via the pyrolysis and gasification processes, on the immobilization of metals/metalloids in soil. Because the processes for these two techniques vary, the feedstocks undergo different heating regimens and, as a result, their respective char products exhibit different physico-chemical properties. Therefore, this study focuses on (1) the characterization of derivative biochar from the bioenergy system to understand their features and (2) an exploration of various biochar impacts on the mobility of As and Pb in contaminated soil. The results showed bioenergy biochars (BBCs) performed well in mitigating Pb extractability (1 M ammonium acetate) with a Pb immobilization >80%, but unfavorably mobilized the bioavailable As, likely because of electrostatic repulsion and ion exchange competition. The BBC surface functional group would chemically bond with the As and remain stable against the pH change. An increment in aromatic carbon would effectively enhance cation-π interaction for Pb immobilization. Nevertheless, an amendment with richer condensed structure and higher inorganic minerals (Ca2+, K+, Mg2+, and Na+) can lead to better performance in retaining Pb.